Rubbing and abrading machines



B. H. MOSBACHER RUBBING AND ABRAVDING MACHINES Original Filed March 2. 1950 June 18, 1957 4 Sheets-Sheet 1 lnz enfor June 18, 1957 B. H. MOSBACHER RUBBING AND ABRADING MACHINES Original Filed lla rch 2, 1950 4 Shets-Sheet 2 n 8, 1957 B. H. MOSBACHER 9 RUBBING AND ABRADING uncnmss Original Filed March 2. 1950 4 Sheets-Sheet I 71 Van/0r June 8, 1957 B. H. MOSBACHER 2,795,901

aussmc AND ABRADING uacnmss Original Filed larch 2, 1950 4 Shets-Sheet 4 Inferior United States Patent RUBBING AND ABRADING MACHINES Bruce H. Mosbacher, Rockford, Ill.

Confinuation of application Serial No. 147,172, March 2, 1950. This application July 28, 1955, Serial No. 524,896

11 Claims. (Cl. 51--170) This invention relates to rubbing and abrading machines and particularly to a reciprocatory *abrading machine adapted to be held manually during use.

An important object of this invention is to provide an improved abrading machine having a single reciprocatory abrading shoe and a novel arrangement for counterbalancing the 'abrading shoe.

Another object of this invention is to provide an abrading machine which is adapted for use in confined spaces and for finishing alongside abutments.

A further object of this invention is to provide an abrading machine having a novel construction for mounting the abrading shoe and counterweight therefor to prevent the entrance of foreign material into the drive mechanism for the shoe and counterweightv Still another object of this invention is to provide an abrading machine which is compact and constructed to be operated and manipulated by one hand.

These, together with various ancillary objects and advantages of this invention will be more readily understood as the same becomes better understood by reference to the following detailed description when taken in connection with the accompanying drawings wherein:

Fig. 1 is a vertical sectional view through the abrading machine, taken on the plane 11 of Fig. 4;

'Fig. 2 is a vertical sectional view taken on the plane 22 of Fig. 3;

Fig. 3 is a horizontal sectional view taken on the plane 33 of Fig. 2;

Fig. 4 is a horizontal sectional view taken on the plane 44 of Fig. 2;

Fig. 5 is a top plan view of the govenor assembly;

Fig. 6 is a horizontal sectional view through the air motor, taken on the plane 6-6 of Fig. 1; and

Fig. 7 is a horizontal sectional view through the air motor and taken on the plane 77 of Fig. 1.

This application is a continuation of my copending application Serial No. 147,172, filed March 2, 1950, now abandoned.

Reference is now made more specifically to the abrading machine shown in the accompanying drawings. The abrading machine is formed with elongated cast body 8 having upstanding side walls 9 and an integral top wall 11. The body is formed with an outwardly extending flange portion 12 around the lower end thereof which is fiat at the underside thereof and a track, designated generally by the numeral 13 is secured to the flange portion as by fasteners 14. The track extend-s completely across the open lower end of the body and defines a chamber 15 therein. The 'abrading machine is arranged to be manipulable with onev hand and for this purpose the side walls 9 are formed with an outwardly flared rim portion 17' around the upper edge of the body to form a finger receivingdepression which extends around the body be low the upper edge thereof. In use, the body is gripped by one hand with the palm overlying the top of the body and the thumb and fingers extending around the rim at opposite sides of the body into the finger receiving de- 7, 2,795,901 Patented June 18, 1957 "ice pression formed between the rim and the flange portion 12. The rim is spaced from the side walls adjacent the upper edge of the side walls and defines an upwardly facing channel 18. A dome shaped operating lever 19 is hinged to the body by a pin 21 and overlies the top wall with the side portions 19a of the cover or lever extending into the channel.

In the embodiment illustrated, the abrading pad is driven by an air motor of the vane type. The air motor includes a casing in the form of an oblong cylinder having top and bottom plates 24 and 25 respectively on the upper and lower ends. The motor is interposed between the track 13 and the top wall 12 of the body and sealed to the latter by a gasket 26 to form a sealed compartment 27 between the top plate and the body. A shaft 28 is rotatably mounted in bearings 29 in the top and bottom plates and a rotor 31 is non-rotatably connected to the shaft, as by a key or spline 32. A plurality of slots 33 are formed in the rotor periphery and vanes 34 are slidably disposed in the slots to form a running seal with the motor casing 23. As best shown in Fig. 4, the rotor is in close running fit at opposite sides thereof and forms diametrically opposed eccentric chambers 23a and 23b.

A connection 35 (Fig. 1) is formed in the body 8 for connecting the machine to a source of compressed air or the like and passages 36 and 37 are formed in the body for communicating the connection to the compartment 27 above the air motor. Conveniently the passage 37 may be formed by drilling a hole in the top wall of the body from the connection 35 to the compartment 27 and then plugging the end of the passage with a plug iii. A valve is provided for controlling the flow of air to the motor and as shown includes a valve member 39 having an operating plunger 41 arranged to engage the underside of lever 19. A spring 42 is provided to norm-ally urge the valve member to its closed position against the valve seat 40 thereby raising the lever 19. A stop 43 is provided on the body for engagement with the lever to limit upward swinging movement of the latter.

The rotor shaft is formed with an axially extending bore 45 which communicates at its upper end. with the compartment 27. Radial ports 46 are formed in the shaft and communicate with the annular passage 47 formed between the rotor and top plate around the shaft to supply =air from the compartment 27 to said passage. A pair of diametrically opposed radial passages 48 (Figs. 4 and 7) are formed in the top plate and convey the air from the pass-age 47 through the ports 49 to the eccentric chambers 23a and 23b. Compressed air from the passages 48 is also supplied through ports 51 in the top plate to the base of the slots 33 in the rotor, as the slots move into registry with these ports, .to apply air pressure to the vanes 34 for counterbalancing-the air pressure acting on the outer edges of the vanes. Arcuate grooves 53 (see Fig 6) are also formed in the bottom plate and arranged to communicate with the base of the slots 33 in the rotor as the slots move thereby. Compressed air is supplied to these grooves by way of a passage 55 (Fig. 1) which extends longitudinally of the rotor and communicates at one end with the passage 47 and at the other end with an annular groove 56 formed in the lower end of the rotor. The groove 56 partially overlies the grooves 53 to supply compressed air thereto and the air pressure in the groove 56 applies an upward thrust on the rotor 31. Preferably, the area of this groove 56 is related to the area of the passage 47 on the upper end of the rotor to counterbalance the "axial thrust on the rotor produced by the air pressure in that passage.

Air is exhausted from each of the eccentric chambers 23a and 23b throughports 58 and 59 (Figs. 6 and7) in the top and bottom walls 24 and 25 respectively, which ports communicate through lateral passages 61 and 62 with the chamber 15 between motor casing and the body. Air is also discharged through ports 63 and passages 64 in the top wall, which last mentioned ports are arranged to communicate with the base of the rotor slots-as the latter move thereby to discharge air from the slots. As is apparent from Fig. 4, the exhaust ports 58, 59 and 63 are circumferentially spaced, in the direction of rotation of the rotor, from the air linlet ports 49, 51 and 53 and produce a pressure differential therebetween which acts upon the rotor vanes and produces rotation of the rotor.

The speed of rotation is controlled by throttling the flow of air to the motor and for this purpose there is provided a governor assembly 66 (Figs. 1 and The governor includes a sleeve 67 slidably disposed in the bore 45 for movement therein to regulate the flow of air through ports 46. A spring 68 is disposed in the bore 45 and engages the inner end of the sleeve to yieldably urge the latter in a direction to open the ports 46. A bracket 69 is attached to the upper end of the shaft for rotation therewith and a pair of flyweights 71 are swingably mounted on the bracket. Fingers 72 are formed on the flyweights and engage the flange 73 on the upper end of the sleeve to urge the latter downward against the bias of spring 68 as the rotational speed of the shaft increases. As is conventional, the weight of the flyweights and the spring 68 are arranged so that the sleeve will be urged downwardly to close the ports 46 when the shaft rotates at a preselected speed and the flyweights release the pressure on the sleeve to open the ports when the shaft speed drops below the preselected speed.

In accordance with the present invention, a single abrading shoe 75 and a counterweight 76 are reciprocably mounted on the track 13 and connected to the shaft 28 to be driven thereby simultaneously in opposite directions. In particular, the track 13 includes a plate 78 secured to the base of the body and sealed thereto by a gasket 79. Depending sides 81 are formed on the plate 78 and inwardly extending flanges 82 are formed on the lower edges of the sides. The abrading shoe includes an open rec tangular frame which underlies the flanges 82 on the track and includes spaced side portions 83a and end portions 83b. Resilient wipers 84 (Fig. 2) formed of felt or the like are attached to the side portions 83a of the frame and engage the underside of the flanges 82. Upright cross members 86 are formed on the end portions 831: of the frame and are shaped to extend between the sides 81 of the track and closely adjacent the plate 78 to form a slidable closure for the ends of the track. Suitable wipers 85 are provided on the cross members to assure a close fit with the track. Roller support blocks 87 are provided adjacent opposite ends of each of the cross pieces 86 and are preferably formed integrally with the latter and with the side portions 83a of the frame. Trunnions 88 are mounted on each of the blocks and rollers 89 are mounted on the trunnions and located in recesses 87a in the blocks 87. The sides of the blocks 87 around the recesses are arranged to engage the side portions 81 of the track to take the side thrust of shoe. As best shown in Fig. 3, the external diameter of the rollers is made to be closely received between the plate 78 and the flange 82 of the track to guidably support the shoe thereon.

The shoe is drivingly connected to the motor shaft for reciprocation thereby and for this purpose an eccentric 91 is nonrotatably keyed to the lower end of the shaft. A crank 93 has one end 93a thereof rotatably connected to the eccentric and the other end pivotally connected to a pin 94 on the cross bar 95 which extends between the roller support blocks at one end of the shoe. The counterweight 76 is also slidably mounted on the track 13 and reciprocated simultaneously and oppositely with the shoe 83 by means of an eccentric 96 on the motor shaft and a crank 97. The crank 97 is rotatably connected at one end 97a thereof to the eccentric 96 and pivotally connected at the other end to a pin 98 on the counterweight. As best shown in Figs. 2 and 3, the width of the counterweight is substantially equal to the spacing between the side portions 81 of the track and the thickness of the counterweight, along the side edges thereof, is equal to the spacing between the flange 82 and the plate 78 of the track so that the counterweight is guided therebetween. The counterweight is shaped at the ends thereof complementary to the opening defined by the roller support blocks 87 and the cross members 86 on the shoe and the length of the counterweight is made less than that of the opening between the roller support blocks and cross members by an amount slightly greater than the sum of the throws of the eccentrics 91 and 96. The counter- Weight thus substantially fills the space within the shoe except for the spacing required to permit relatively opposite movement between the shoe and counterweight and provides the desired mass for the counterweight in a minimum of space. An elongated central opening 101 is formed in the counterweight and dimensioned to provide clearance for the motor shaft and eccentrics 91 and 96, and recesses 102 and 103 are formed in the lower and upper faces respectively of the counterweight to provide clearance for the cranks 93 and 97.

A plate 105 is attached by fasteners 106 to the underside of shoe 75 to close the bottom of the frame and a pad 107 is affixed to the bottom of the shoe to provide a resilient backing for a sheet of abrasive (not shown). The abrasive sheet is clamped to the shoes by means of clamps 169 located at opposite ends of the shoe and extending upwardly therefrom. In accordance with the present invention, the clamps each include a pair of spaced upstanding ears 111 on the end portions 83b of the frame. A lever 112 is disposed between the ears and pivotally attached thereto by a pin 113. A laterally extending arm 114 is formed on the lever and rollers 115 are rotatably mounted on the arm adjacent opposite sides thereof. A U-shaped clamp member 116 is formed with inwardly extending tabs 117 on the bight portion thereof and is pivotally attached by fasteners 118 to the ears. The central portion of the U-shaped member is open at 119 to permit the lever 112 to movably extend therethrough and the outer edge 121 of the member is curved to provide a grip portion for the abrasive sheet. The lever is of the over-center type and the roller engages one side of the U-shaped member as the lever is moved to an upright position to thereby urge the opposite side of the member into clamping position. The roller passes the center of the pin 113 to the position shown at the left in Fig. l and releasably locks the lever in the clamp position thereof. Oppositely extending fingers 122 are provided on the lever for engagement with the outer side of the U- shaped member as the lever is moved to its release position shown at the right in Fig. 1 to move the member out of its clamping position.

In order to minimize vibration of the machine in operation, the dynamic mass of the counterweight is made substantially equal to the dynamic mass of the shoe 75. As shown in Fig. 3, the throws of the eccentrics 91 and 96 are equal and hence the weight of the counterweight 76 is made equal to the weight of shoe 75. As is apparent, the cross members 86, the support blocks 87, rollers 89 and clamps 109 are attached to the frame of the shoe and extend thereabove so that the center of mass of the shoe is spaced above the frame and located approximately at the center of mass of the counterweight. Moreover, in the single abrading shoe and counterweight arrangement illustrated, the counterweight and shoe are located at the approximate longitudinal center of the machine when in the position shown in Fig. 3 and move therefrom simultaneously in opposite directions so that there is no effective shifting of the center of mass of the overall machine andfurther, there is little relative shifting between the center of the abrading shoe and the abrading machine as the shoe is reciprocated.

The shoe is arranged to define a substantially closed chamber with the track 13, which chamber houses the defined between the track and the abradin'g sho'e. maintains the last mentioned chamber "at above atmosdrivemechanism for connecting the 'shoe and counterweight to the motor-shaft. This'efiectivel'y precludes the entrance of foreign matter, such as the material abraded by the machine, into the operating mechanism therefor. Further, the air discharged from the motor, through passage 61 and '62 into the chamber 15, 'is passed through ports 125 in the plate 78 (s'ee'Fig. 1) into the -charnber This pheric pressure to aid in'excludin'g'fore'ign material therefrom and, since'the air supplied to the motor carries a lubricant for the motor, this lubricant is 'appliedtothe operating p'arts in'the track chamber. Additionally, the chamber '15 and the track chamber serve to imiflie the noise of the exhaust air.

What is claimed as new is:

I. In 'a rubbing machine, {the combination of a body shaped and dimensioned to be held manually, a 'track mounted beneath said bodyyapfad' dimensioned wider a'rid longer than'said body and rnounted on said'trackfoniectilinear reciprocation to extend beneath the track outwardly of thesides and ends of s'aid body i'nall operative positions of the pad, a counterweightdimensioned-shorter and narrowertha'n sai'd'pad and mounted on saidtrack for rectilinear reciprocation beneath said body above "said pad to lie in all of its operative positions within the periphery ofsaidpad, and a motor mounted in saidbody and havingconn'ections to the pad and the counterweight for effecting simultaneous reciprocation of'the pad and counterweight in opposite directions.

2. A single pad rubbing machine comprising-'21 body shaped and dimensioned to beheld manuall /ya track mounted on said body 'to'extend' therebeneath, a motor in said body, 'a pad having *a length and *width g'ieaterthan the length and'widthof s'ai'd'body andmounte'd'for' rec'tilinear reciprocation on the' track in "spacedrelatio'n to 'the underside of the body toextend outwardly of the-sides and end of the body in all operative positionsof the pad, a counterweight mounted for rectilinear reciprocation on said track at the underside of said bo dy 'above the pad, said counterweight having alength and width less than the length and width of the pad to lie in all operative positions of said pad and counterweight within the periphery of saidpad, said track and pad having p ortions extending around said counterweight to substantially completely enclose the latter, and driving connections from the motor to the pad and to the counterweight to reciprocate the pad and counterweight simultaneously and oppositel y in reof the motor, said counterweight havsponse to operation ing adynamic mass substantially equal to the dynamic mass of the pad to counterbalance the'p'ad as the pad and counterweight reciprocate oppositely.

3. In a rubbing machine, the combination of a housing body, a stationary track attached to said housing body at the underside thereof and extending therebeneath, a pad mounted for rectilinear reciprocation on said track and formed with a working surface at its underside disposed beneath the track and dimensioned to extend at least the full length of the housing body, a counterweight dimensioned shorter and narrower than said pad and mounted for rectilinear reciprocation on said track to he in all of its operative positions above said pad within the periphery thereof and below said body, said counterweight having a dynamic mass substantially equal to the dynamic mass of said pad and having an elongated opening therein, a motor mounted within said housing body and having a vertically disposed drive shaft extending downwardly through the opening in said counterweight and terminating above said pad, and means connecting said shaft to each said pad and said counterweight for reciprocating them simultaneously in opposite directions.

4. In a rubbing machine, the combination of a housing body, a stationary track attached to said housing body and presenting opposite track portions located at op- 6 :posite sidesofsaidbody andextehdingtherebene'ath, a pad mounted 'for rectilinear reciprocation on said track in spaced relation to the underside of said body and having opposedside portions disposedin Wiping contact with said 5 track portions, said-padhaving opposed end portions ex-- tending "upwardly therefrom between the track portions and-disposed in'w'iping contact with the underside of said body to define a chamberat th'eu'riderside of the housing bodyabove thepad, saidpad being-formed With'a working '10 surface at its underside, a-counterweight-having a dynamic from said motor to'lubricate the operating parts at *said chamber.

5. In a rubbing machine, a housing body, a stationary track attached to said housing body at the underside therearena extendingtherebeneath, a motormounted in said housing body and having a drive shaft'extending down- "wa'rdly the'r'efrom,a pad having a-Worki'ng surface on its underside dimensioned Wider and 'longerthan said body and mounted for rectilinearreciprocation on the track to H extend outwardly of said body-in'all operativelpositionsof 'the pa'd, means op'eratively connecting the pad to theshaft for 'reoiprocation' about axposition' in which the padis located substantially symmetrically of the housing body, spaced antifricti'o'n means carriedby said pad adjacent I, opposite'endsthereof and mounted on said 'trac-kto ride therealo'ng, a counterweight having adynamic mass equal tothe' dynamic 'mass'of the pad mounted for'rectilinear reciprocation 'on 'said tr'ack directly above the central por- "tion "Qf s'aid a'd and'bel'ow the underside of body, said counterweight havin "a length and width less than the 10 length'andwidth ofsai'd -padand mounted to l-ie'within the periphery thereof in all operative positions of saidpa'd, and means c'o'nnecting'said shaft to said counterweight to reciprocate the latter simultaneously and oppositely with "the reciprocation of 'said pad.

*6. In a'rubbingmachine, the cornbination'of a housing "body,"'aplate attached to the underside of saicl'body to extend substantially the full length thereof and depending side portions along opposite sides of said plate, inwardly 7 "extending flanges on the tower edges of said side portions defining a track therewith, a'pad' 'positioned beneath the fiangesand having 'a'len'gth and width "greater than the length and'width' of said'housing bodyto extend outwardly therefrom in all operative positions of the-pad, said pad having a working surface at its underside and portions adjacent opposite ends thereof extending upwardly between the opposed side portions on said plate, pairs of spaced rollers on said upwardly extending portions on said pad adjacent opposite sides of said pad and guidably disposed between said plate and the flanges on said sideportions to support the pad for reciprocation along the track, a counterweight having a dynamic mass substantially equal to the dynamic mass of the pad slidably mounted on said depending side portions and extending therebetween, said counterweight having a length less than the spacing betweenn said upwardly extending portions on said pad to be located in all of the operative positions of said pad and counterweight between the paid and plate and intermediate the upwardly extending portions on said pad, a motor in said housing body, and driving connections from said motor to said pad and counterweight for reciprocating said pad and counterweight simultaneously in opposite directions.

7. In a rubbing machine, the combination of a housing body, a plate attached to the underside of the body to extend substantially the full length thereof, depending side portions on opposite sides of said plate, inwardly extending flanges on the lower edges of said side portions and defining a track therewith, a pad positioned beneath the flanges and having a working surface on the underside thereof, cross members located adjacent opposite ends of said pad and extending upwardly therefrom into closely spaced adjacency with said plate and the side portions of the track to form slidable closures for the ends of the track and define a chamber therein, means mounting pairs of spaced rollers adjacent opposite ends of said cross members and within said chamber, said rollers being disposed between said flanges and said plate to guidably mount the pad thereon, a counterweight disposed in said chamber and extending between said side portions in sliding engagement with said plate and said flanges, said counterweight having a central opening therein, a motor disposed in said body above said plate and having a drive shaft extending through said plate into said chamber, said shaft extending through said opening in said counterweight, and means in said chamber operatively connecting said pad and said counterweight to said shaft for reciprocation thereby simultaneously in opposite directions.

8. The combination of claim 7 wherein said motor is an air motor, and passage means for passing the exhaust air from the motor into said chamber.

9. In a rubbing machine, the combination of a body having upstanding side walls and, a top wall, said body being open at the lower end thereof, a track including a plate attached to said body and extending across the open lower end thereof to define a chamber within said body,

an air motor mounted in said chamber, inlet passage means for supplying compressed air to said motor, discharge passage means for discharging air from said motor into said chamber in the body, depending side portions on opposite sides of said track, inwardly extending flanges on the lower edges of said flanges, asingle abrading pad underlying said flanges, cross members located adjacent opposite ends of said pad and extending upwardly therefrom into closely spaced adjacency with said plate and side portions of said track to form slidable closures for the ends of said track and define a chamber therein, said plate having ports therein for passing exhaust air from the chamber in the body into the chamber in the track, means slidably mounting the shoe on said track, a counterweight disposed within the chamber in said track between said plate and said pad, said counterweight extending between the side portions of the track in sliding engagement with said plate and said flanges, and means for operatively connecting said pad and the counterweight to said motor for reciprocation thereby simultaneously in opposite directions.

10. In a rubbing machine, the combination of a housing body, a stationary track attached to the underside of the body and presenting opposed track portions located at :opposite sides of the body and extending therebeneath, a

track portions, said pad having opposed end portions extending upwardly therefrom between the tracktportions and disposed in wiping contact with the underside of the body to define a chamber at the underside of the body above the pad, said pad being formed with a working surface at its underside, a counterweight having a dynamic mass equal to the dynamic mass of the pad mounted for rectilinear reciprocation on said opposed track portions to extend therebetween within the chamber defined by said pad and track, a motor in said housing body, and means drivingly connecting the motor to the pad and counterweight to reciprocate them simultaneously in opposite directions.

11. In a rubbing machine, the combination of a housing body, a stationary track attached to the underside of the body and presenting opposed track portions located at opposite sides of the body and extending therebeneath, a pad mounted for rectilinear reciprocation on said track in spaced relation to the underside of said body and having opposed side portions disposed in wiping contact with the track portions, said pad having opposed end portions extending upwardly therefrom between the track portions and disposed in wiping contact with the underside of the body to define a chamber at the underside of the body above the pad, said pad being formed with a working surface at its underside, a counterweight having a dynamic mass equal to the dynamic mass of the pad mounted for rectilinear reciprocation on said opposed track portions to extend therebetween within the chamber defined by said pad and track, a motor in said housing body, said counterweight having an enlarged central opening therein, a motor on said shaft extending through said opening, and means located within said opening in said counterweight for reciprocating said pad and counterweight simultaneously in opposite directions.

References Cited in the tile of this patent UNITED STATES PATENTS 1,954,489 Partlow Apr. 10, 1934 2,103,444 Bauch Dec. 28, 1937 2,334,172 Champayne Nov. 16, 1943 2,418,246 Burleigh Apr. 1, 1947 2,437,152 Burleigh Mar. 2, 1948 2,618,107 Martin Nov. 18, 1952 FOREIGN PATENTS 386,399 Great Britain Jan. 19, 1933 686,363 Great Britain Jan. 21, 1953 

